Electric meter.



Patented lune I0, |902.

E. THOMSON.

ELECTRIC METER.

(Application med occ. 2s, 1900.)

2 Sheetws-Sheet l.

f mi (No Model.)

Patented lune lo, |902.-

y E. THoMsoN.

ELECTRIC METER.

(Application led. Oct. 23, 1900.) (No Model.) 2 Sheets-Sheet 2.

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UNTTED STATES PATENT OFFICE; y

FIJI-IU THOMSON, OF SVAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO GENERAL kELECTRIC COMPANY, A CORPORATION OF NEWKYORK.

ELI-:orale METER.

SPECIFICATION forming part of .Letters Patent' No. 701,965, dated June 10, 1902. Application iiled October 23, 1900. Serial No. 34,017. (No model.)

To @ZZ whom, t may concern.:

Be it known that I, ELIHU THOMSON, a citizen of the United States, residing at Swampscott, county of Essex, State of Massachusetts, have invented certain new and useful Improvementsf in Electric Meters, (Case No. 1,495,) of which the following is a specification.

My invention relates to electric meters, and

i 'Io has for its object to produce a new and improved meter for measuring alternating electric currents which shall be simple in construction, light in weight, and effectivein operation. j

I5 The invention comprises a new arrangement for obtaining the desired .phase displacement of the shunt-field in an alternating-current meter, a new arrangement for transmitting motion from the driving-shaft zo to the recording mechanism, a new arrangement of the terminal connections, whereby the meter may be readilyinstalled or removed,

and certain details of construction hereinafter described. v. The character of my invention will be better understood by reference to the following speciication, taken infconnectionwithv theA accompanying drawings,"while'its scope will .be pointed out in the appended claims.

3o Referring to the drawings, which show my inventionv applied to a meter of the induction type, Figure l is a front elevation of the improved meter; Fig. 2, a side elevation thereof; Figs. 3, 4, and 5, detai'lviews of parts of the meter; Fig. 6, a diagrammatic view showing the actuating elements of the meter together with their circuit connections; Fig. 7, an enlarged front elevation of the actuating elements; and Fig. 8 is an enlarged view in 4o partial cross-section, showing a coating of non-magnetic material on the armature-shaft of the'nieter.

Referring particularly to Figs. l and 2, D is a disk armature mountedV on a shaft X, supported at its lowerendina jewel-bearing, as usual. A portion of this armature is included between the poles of the permanent magnet ll/Lwhich constitutes the retarding-magnet for the meter. At a point removed from the re- 5o tarding-magnet and above the armature is lo'- 'cated a series coilS. On the other side of the u armature and arranged in a plane parallel thereto is located the shunt-magnet,co1npris ing a laminated iron core I'andfa seriesof coils K, surrounding said core. The shuntmagnet is so positioned that the freepoles of the laminated core lie directly below'the cen-V I ter of the series coil on either side thereof. Interposed between the polesof Athe magnetcore is a mass of conducting material C, the 6o function of which will' hereinafter be described.

. The structure of the sh unt-magnet is shown'.

in planin Fig. '3 and in front elevation in Fig. 7. The coils K, constituting the shunt-winding, are connected in series with one another across the mains through which the current to be measured is supplied. It is not necessary that the core of the shunt-magnet should be constructed as is shown in theV drawings. 7o

It may be madeof a dierent form than that shown jor it may be constructed in sections. The object of the construction shown is to secure as high an induc'tance as possible im theshunt-circuit, so that the free shunt-field 7.`5 maybe as nearly as possible inv quadrature with the electromotive force impressed on the shunt-circuit. l 1 y Thefree field across the gap between the polesr ofthe laminated ring I would naturally 8o vtend to be greatest directly across thespace between the poles and would have aphase displacement somewhat less than ninety degrecs behind the eld'due to the series coil on non-inductivev loads. In order to deflect'this 85 free field towardthe armature and at the same l time to give this deliected field a certain increased phase displacement up to ninety degrees on non-inductive load, I insert into this gap-a body of copper or other suitablecon- 9o ducting material C'. vThis body ofcopper has a thick portion constitutingaheavyinclosing circuit around theiu'x between the `poles of vthe ring-I. The flux being'rapidly alternating in characterfcannot easily passjthroughthe heavy cond'ucting-ciifcu'it' wlihfl the copper piece presents, and therefore tends to be deflected,- so as to pass around the same. This deflection is produced in virtue of the induced currents set up in the copper piece C. In orroo der that the deflection may be toward the armature, the copper body is provided with a portion extending laterally beneath the poles of the shunt-magnet and is also made of considerable width, so that the shortest path around the copper mass is over the top of the portion projecting upwardly between the magnet-poles.

The magnetic fiux which actually passes over the part C and affects the armature D comprises two components, one of which consists of a portion of the main shunt-flux actually diverted around the mass C and the other of which consists of a flux due to the induced currents set up in the copper mass itself by that portion of the main shunt-flux which threads the said mass. By properly proportioning the parts the resultant flux which affects the armature D may be made to lag by substantially ninety degrees behind the electromotive force of the circuit in which the meter is included.

In order that the iux may be caused to cut the armature D, it is desirable that the mass C be extended until it almost touches the armature, and, as already stated, in order that the flux may not be diverted in other directions it is desirable that the copper mass be extended to a considerable distance both below and at the sides of the shunt-magnet poles. The mass of copper tends, as it were, to shield the free field and to concentrate the effect on the armature, and at the same time it produces a field acting on the armature which is slightly later in phase than the magnetic flux induced in the core of the shunt-magnet.

The coils K K, constituting the shunt-winding, may be wound separately and inserted in the gap between the poles of the ring I, and so slipped upon the ring before the piece C is placed in position.

In Fig. 6 the circuit connections of the meter are shown. They are the connections usually employed in .induction-wattmeters. The series coil is included directly in circuit with the mains W, and the shunt-coils, connected in series with each other, are connected between the mains W and W'. The copper piece C is shown in this figure, and the position of the meter-disk with respect to the shunt and series magnets is indicated in dotted lines. With the arrangement described the armature-disk will not rotate unless current is flowing in the winding S, and its speed of rotation will be proportional to the energy to be measured.

Themanner in which the shunt and series windings are supported in position in the meter is shown most clearly in Figs. l and 7. The series coil S is adjustably supported from the meter-frame by means of two brass clips B, which are provided with T-shaped ends arranged to be bent over the edges of the coil. The shunt-magnet is supported on bosses extending upwardly from the base or frame of the meter and is fastened in position by two screws V and V'. This construction is shown most clearly in Fig. 7, from which it will be seen that the screws V V' are passed through the ends of the shunt-magnet core and through openings in the lateral extensions of the copper piece Cinto the framework of the meter. The screws V and V may be made of iron, if desired, and the heads may be enlarged to project upwardly toward the armature D, so as to assist in determining the iux in this direction, or the ends of the laminze of the shuntmagnet may be bent upwardly for the same purpose. Although the screws V and V' project, as indicated in dotted lines in Fig. 7, into the framework of the meter, no harmful effect is produced, even though the screws are constructed of iron, for they are each surrounded by a mass of copper where they pass through the lateral projections of the piece C.

In order to reduce as much as possible the friction of the moving parts of the meter and at the same time to render it possible to make the parts small and compact, I interpose a magnetic gearing between the meter-shaft and the recording mechanism. This gearing comprises a thin disk Y, of magnetic material, so positioned that it has a rolling engagement with the shaft X, which is constructed of some magnetic material, preferably of soft steel and which may be slightly magnetized. The disk Y is mounted on a shaft of magnetic material, the lower end of which is pivoted in a bearing p in proximity to one of the poles of the retarding-mag'net M. The supports for the dierent parts of the meter are constructed of brass or other non-magnetic material,and therefore the magnetism induced by the retarding-magnet in the shaft upon which the disk Y is mounted finds a nearly-closed circuit of magnetic material through thedskY and the shaft X back to the other pole of the permanent magnet. The amount of sticking between the edge of the disk Y and the shaft X may be nicely adjusted, so that the disk may be rotated as the shaft X revolves without any considerable frictional resistance. The upper pivot of the shaft upon which the disk Y is mounted is of course made free enough to permit the shaft and the disk to always remain in engagement.

In order to prevent actual magnetic contact between the shaft and the disk, a thin coating of non-magnetic material, such as brass or copper, may be applied either on the shaft or on the edge of the disk, or, if desired, both may be coated. In Fig. 8 I have shown such coating Z on the armatureshaft.- The shaft upon which the disk Y is mounted is provided with a worm-gear t, which through suitable gearing actuates the recording mechanism in the usual manner. With the arrangement j ust described a very slight torque exerted on the armature D is suiiicient to turn the disk Y through the shaft X, and the advantage of the leverage obtained by this construction materially reduces the retardn IOO IIO

` the friction be considerably increased, but

. nals are arranged to engage with correspondf the parts could not be made so delicate or so small as is possible with the constriction shown, and, as already stated, it is one ot' the objects of my invention to so construct the meter that it shall be small andcompact.

The mechanisln of the meter may be covered by any suitable protecting-casing, as is indicated inv dotted lines in Figs. 1 and 2.

Below the compartment containing the actuating mechanism of the lmeter I have provided, as will be seen from an inspection of Figs. l and 2, a separate compartment F, containing ixed 'terminals T, to which the meter-windings are connected. These termiing terminals T2, carried uponl a base or back plate P and placed in permanent connection with the wiring of the building in which the meter is to be installed.` By this construction it is possible to wire a building for the installation of a meter without leaving loose ends to be connected tothe terminals of the meter-windings. Further', the placing of the meter in position automatically completes the necessary circuit connections, and since the terminals are contained in a compartment separatefrom the compartment containing the operating parts the meter may` beinstalled or removed without removing the protecting-casing therefrom, and therefore without danger of injury to the actuating mechanism of the meter. `The particular type'of meter shown in the drawings requires three terminals arranged to engage with corresponding terminals connected to the house-wiring; but this feature of my invention is evidently not limited to any particular number of terminals or to any particular type of meter.

vThe base or back plate P, upon which the terminals connected to the house-wiring are mounted, may be arranged to constitute a support for the meter, and to this end I have shown this back plate lprovided with lugs or projectionsL and the meter-casing with corresponding lugs L2, having openings therein adapted to receive the projections L. In order t'o hold the meter in position, a set of keys may be inserted transversely in slots in the projections L. 4 Such keys are indicated at J J, Fig. l. In order to prevent an unauthorized removal vot' the meter, these keys may be secured in place by the wires and lead seals shown at N N. The form of fastening device by which the meter is` held to the base or back plate may evidently be widely Varied without departing from my invention.

The construction and arrangement of the terminals T2 may also be widely varied, and the compartment F, containing the corresponding terminals T, may, if desired, beentirely isolated from the main compartment of the meter.l As shown-in the drawings, there is an opening between the two meter-coml partments, this opening being provided so that the permanent retarding-magnet may be arranged to engage therewith.f -v

2. A connection-board for electric meters, comprising a base and a set of terminals mounted thereon constructed and arranged to engage corresponding terminals connected `to the meter windings when the meter ,is

placed in position.

3. A connection-board for electric meters, compri-sing a base, a set of terminals mounted thereon constructed and arranged to engage corresponding terminals connected to the meter-windings when the meter is placed in position, and means for fastening the meter'to saidr base. v

4'. A connection-board for electric meters, comprising a base, a set of terminals mounted thereon constructed and arranged to engage corresponding terminals connected to the meter-windings when the meter is placed 'in position, and fastening devices for the meter also mounted on saidbase.

In an electric meter, a set of terminals supported from the meter-frame and 'connected to the meter-windings, said terminals being constructed and arranged to engage a corresponding set of terminals, connected to line, 105

when the meter is placed in position. v

j 6. In combination in an electric meter, a separate compartment, and a set of terminals to Which the meter-windings are connected mounted therein, said terminals being constructed and arranged to engage a correspond-l ing set of terminals connected to' line. y'

7. In combination, in an electric meter, a compartment containing the actuating mechanism of said'meter and a separate compartment containing a set of terminals to which the meter-windings are connected, said terl minals being constructed and arranged to engage correspondingy terminals connected to line. l'

8. An electric meter provided with terminals to which the meter-windings are connected, said terminals being constructed and ar- IOO ranged to engage corresponding terminals-on the vmeter-support when in' position.` 9.A An electric meter provided withterminals to which the meter-windings are connected, said terminals being constructedand arranged to engage corresponding terminals on the meter-support when the meter is placed in position, and means for fastening said methe ymeter is'placed v I ter in position on said support.r f

10. In an electric meter, a magnetized meter-shaft and a magnetized disk in rolling engagement therewith.

11. In an electric meter', a magnetized meter-shaft, a magnetized disk in rolling engagement therewith, and a layer of non-magnetic material interposed between said shaft and said disk.

12. In an electric meter, a shaft of magnetic material, a disk of magnetic material in rolling engagement therewith, and means for magnetizing said disk and shaft.

13. In an electric meter, a shaft of magnetic material, a disk of magnetic material in rolling engagement therewith, and operatively connected to the recording mechanism, and means for magnetizing said shaft and disk.

14. In combination in an electric meter, a magnetized meter-shaft, a magnetized disk in rolling engagement therewith and means for transmitting the motion of said disk to the recording mechanism.

15. In combination in an electric meter, a permanent magnet, a shaft of magnetic material adjacent to one of the poles of said magnet, and a disk of magnetic material mounted on said shaft and arranged to have a rolling engagement with the main driving-shaft of the meter.

16. In combination in an electric meter, a retarding-magnet, `and a magnetic gearing between the driving-shaft and the recording mechanism, arranged to be magnetized by said magnet.

17. In combination in an electric meter, a main driving-shaft of magnetic material, an armature of conducting material mounted thereon, a retarding-magnet having its poles extended to include a portion of said armature, a second shaft operatively connected to the meter recording mechanism, and a disk of magnetic material mounted on said shaft and arranged to have a rolling engagement with the main driving-shaft of the meter, said shafts and said disk being so positioned with respect to the retarding-magnet, that they are magnetized thereby.

18. In an electric meter a means for producing a shunt magnetic iiux, lagging by substantially ninety degrees behind the flux due to the series winding on non-inductive load, comprising, in combination, a core of magnetic material constituting a nearly-closed magnetic circuit,a windin g thereon connected across the mains, and a mass of conducting material interposed between the poles of said core.

19. In an electric meter a means for producing a shunt magnetic Jinx, lagging by substantially ninety degrees behind the lnx due to the series winding on non-inductive load, comprising, in combination, a core of magnetic material constituting a nearly-closed magnetic circuit, a winding thereon, comprisinga plurality of coils separated from one another, connected and across the mains, and a mass of conducting material interposed between the poles of said core.

20. In an electricmeter an armature of conducting material, a shunt-winding having its magnetic axis so positioned that it does not intersect said armature, and means for diverting a portion of the shuntflux toward the armature.

21. In combination in an electric meter, an armature, a series winding having its magnetic axis substantially at right angles to said armature, a shunt-winding having its magnetic axis substantially parallel to the surface of said armature, and means for diverting a portion of the shunt-flux toward the armature. j

22. In an electric meter an armature of conducting material, ashunt-winding havingits magnetic axis substantially parallel to the surface of the said armature, and means for diverting a portion of the shunt-flux toward the armature.

23. In an electric meteran armature of conducting material, a shunt-winding provided with a core of magnetic material having its magnetic axis substantially parallel to said armature, and a body of conducting material, constituting a closed circuit, interposed between the poles of said core.

24. In an electric meter, an armature of conducting material, a shunt-winding provided with a core of magnetic material having its magnetic axis substantially parallel to said armature, and a body of conducting material interposed between the poles of said core and extending into proximity to the meter-armature, the said body being so extended in other directions that the shortest magnetic path around the body of conducting material is on the side adjacent to the'armature.

25. In an electric meter an armature of conducting material, a shunt-winding provided with a core of magnetic material having its magnetic axis substantially parallel to said armature, and a body of conducting material interposed between the poles of said core, said body having portions extended laterally beyond the said poles on the side away from the armature.

26. In an electric meter, an armature of conducting material, a shunt-winding provided with a core of magnetic material substantially concentric with said armature, and means for diverting a portion of the shuntiiux toward the armature.

27. In combination, in an electric meter, a metallic armature, a series winding adjacent to said armature on one side, a shunt-winding, provided with a core of magnetic material, located on the other side of said armature and having its magnetic axis substantially parallel thereto, said core being so positioned that its free poles lie opposite to said series winding, and means for diverting a por tion of the shunt-flux toward the armature.

2S. Ig combination, in an electric meter, a

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metallic armature, a series Winding adjacent to said armature on one side, a shunt-Winding provided with a core of magnetic material located on the other side of said armature and havingr its magnetic axis substantially parallel thereto, said core being so po sitioned that its free poles lie opposite to series Winding, and a body of conducting materialinterposed between the poles of said core and extending into proximity to the meter-armature, the saidbody being so extended in other directions that the shortest magnetic patch around the body of conduct` ing material is on the side adjacent tothe armature.

30. .As a means for deflecting ux toward an armature, conducting material in the nyor-y A mal path of said flux.

In Witness VWhereofl have hereunto set my hand this 20th day of October, 19OQ.

ELIHU THOMSON.

Witnesses 4 DUGALD MCKILLOP, y J oHN J. WALKER, 

